This invention relates to apparatus and methods for preserving the identity of the first one of a series of error conditions, each of which can give rise to a machine check interrupt in a data processing system. Indications of other error conditions which may result from propagation of the original error are also preserved for subsequent analysis.
It is common in modern electronic data processing systems to have various indicators for showing that certain error conditions have occurred. Typically, these error conditions may be used to cause one or more functional units of the system to stop. However, subsequent to the occurrence of the error, but before the functional unit actually stops, the original error may propagate and cause other error indications to occur. Thus, when the unit finally stops, more than one error indication may be present, making it difficult to determine which error initiated the stoppage.
The prior art has, in some situations, dealt with the problem by using time-consuming analysis techniques to find which of several error indications most probably occurred first. Not only do these analyses take time, but they do not always give correct results.